If you are logged in, then to the left of a post, below the posters' name, there is a small section called Cheeses: 3, this is a counter for how many Thumbs Up +1 less Down -1, that person has received, a rough measure of their credibility.

After 5 posts, Users can give other Users (not themselves), a Thumbs Up or Down at any time on any post by just clicking on the button below the Cheeses: 3 counter.

There is no financial reward, just an Attaboy/Kudo's sytem. So if you feel someone has been helpful, give them a thumbs up, if you believe they have been distrupting, give them a thumbs down.